MD5 hashing in Android

Question

I have a simple android client which needs to \'talk\' to a simple C# HTTP listener. I want to provide a basic level of authentication by passing username/password in POST r

Answer 1

If using Apache Commons Codec is an option, then this would be a shorter implementation:

String md5Hex = new String(Hex.encodeHex(DigestUtils.md5(data)));

Or SHA:

String shaHex= new String(Hex.encodeHex(DigestUtils.sha("textToHash")));

Source for above.

Please follow the link and upvote his solution to award the correct person.

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Maven repo link: https://mvnrepository.com/artifact/commons-codec/commons-codec

Current Maven dependency (as of 6 July 2016):

<!-- https://mvnrepository.com/artifact/commons-codec/commons-codec -->
<dependency>
    <groupId>commons-codec</groupId>
    <artifactId>commons-codec</artifactId>
    <version>1.10</version>
</dependency>

Answer 2

Here is an implementation you can use (updated to use more up to date Java conventions - for:each loop, StringBuilder instead of StringBuffer):

public static String md5(final String s) {
    final String MD5 = "MD5";
    try {
        // Create MD5 Hash
        MessageDigest digest = java.security.MessageDigest
                .getInstance(MD5);
        digest.update(s.getBytes());
        byte messageDigest[] = digest.digest();

        // Create Hex String
        StringBuilder hexString = new StringBuilder();
        for (byte aMessageDigest : messageDigest) {
            String h = Integer.toHexString(0xFF & aMessageDigest);
            while (h.length() < 2)
                h = "0" + h;
            hexString.append(h);
        }
        return hexString.toString();

    } catch (NoSuchAlgorithmException e) {
        e.printStackTrace();
    }
    return "";
}

Although it is not recommended for systems that involve even the basic level of security (MD5 is considered broken and can be easily exploited), it is sometimes enough for basic tasks.

Answer 3

The accepted answer didn't work for me in Android 2.2. I don't know why, but it was "eating" some of my zeros (0) . Apache commons also didn't work on Android 2.2, because it uses methods that are supported only starting from Android 2.3.x. Also, if you want to just MD5 a string, Apache commons is too complex for that. Why one should keep a whole library to use just a small function from it...

Finally I found the following code snippet here which worked perfectly for me. I hope it will be useful for someone...

public String MD5(String md5) {
   try {
        java.security.MessageDigest md = java.security.MessageDigest.getInstance("MD5");
        byte[] array = md.digest(md5.getBytes("UTF-8"));
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < array.length; ++i) {
          sb.append(Integer.toHexString((array[i] & 0xFF) | 0x100).substring(1,3));
       }
        return sb.toString();
    } catch (java.security.NoSuchAlgorithmException e) {
    } catch(UnsupportedEncodingException ex){
    }
    return null;
}

Answer 4

I have made a simple Library in Kotlin.

Add at Root build.gradle

allprojects {
        repositories {
            ...
            maven { url 'https://jitpack.io' }
        }
    }

at App build.gradle

implementation 'com.github.1AboveAll:Hasher:-SNAPSHOT'

Usage

In Kotlin

val ob = Hasher()

Then Use hash() method

ob.hash("String_You_Want_To_Encode",Hasher.MD5)

ob.hash("String_You_Want_To_Encode",Hasher.SHA_1)

It will return MD5 and SHA-1 Respectively.

More about the Library

https://github.com/ihimanshurawat/Hasher